We have recently completed an epidemiologic survey of cardiovascular risk factors and diabetes in Mexican Americans and Anglos living in San Antonio, TX. Our current results indicate that Mexican Americans have excess diabetes and related cardiovascular risk factors over and above that which can be explained on the basis of their excess obesity alone. In the present project we propose to carry-out a further epidemiologic survey aimed at elucidating the additional factors beyond obesity which contribute to diabetes and cardiovascular risk in this ethnic group. We plan to test two new hypotheses relating to insulin resistance which flow directly from our current results. We will study 3,858 Mexican American and Anglo men and women (ages 25-64) randomly sampled from the San Antonio population. Sampling will be carried out in such a way that we will be able to match Mexican Americans and Anglos on obesity, thereby enabling us to study ethnic differences in diabetes and cardiovascular risk factors independent of the confounding effects of obesity. To further our long-range objective of elucidating the lifestyle vs. the genetic contribution to diabetes and cardiovascular risk in Mexican Americans we will continue to study acculturation and genetic markers (including gene polymorphism and HLA phenotyping) in the new project. By pooling the new project with the original data base we will have a sufficiently large sample for an eventual prospective epidemiologic study of diabetes and cardiovascular risk factors in Mexican Americans which is one of our long-range objectives. We also plan to study the relative prevalence of diabetic complications in 400 Mexican American and Anglo diabetics (195 from our original survey and 205 projected in the new survey). The assessment of complications will include the following: eye, visual acuity, tonometry, fundus photography; renal, serum creatinine, urinary protein, urine cultures; neurological, nerve conduction studies and vibratory sensory threshold; and peripheral vascular, resting and post-ischemic ankle blood pressures by Doppler ultrasound.